chore(deps): update dependency com.google.cloud:google-cloud-bigtable to v1.21.3 (#696)

Author: renovate-bot

samples/install-without-bom/pom.xml

@@ -29,7 +29,7 @@
     <dependency>
       <groupId>com.google.cloud</groupId>
       <artifactId>google-cloud-bigtable</artifactId>
-      <version>1.21.2</version>
+      <version>1.21.3</version>
     </dependency>
     <!-- [END bigtable_install_without_bom] -->